1.Field of the Invention
This invention relates to a catalyst suitable for effective exchange of hydrogen isotopes between gaseous hydrogen and liquid water, and to a process for producing a support or carrier for said catalyst.
2. Description of the Prior Art
U.S. Pat. No. 2,690,379 and Japanese Patent Publication No. 869/1959 disclose that an exchange reaction of heavy hydrogen occurs when heavy hydrogen-containing hydrogen is reacted with water with the aid of a catalyst composed of a relatively inert support having deposited thereon particles of at least one of nickel, cobalt, ruthenium, rhodium, palladium and platinum. It is known that in this method, the catalyst induces an exchange reaction of hydrogen isotopes between hydrogen and steam. However, when this catalyst contacts liquid water, a large and unfavorable loss of activity results.
Japanese Patent Publication No. 32800/1976 (corresponding to French Patent No. 2,355,553) discloses a catalyst comprising an inert support and a sealing coating thereon which is water resistant (i.e., impermeable to liquid water) but is permeable to steam and hydrogen gas. Typical examples of the sealing coating include silicone resins, polytetrafluoroethylene, and a perfluoroethylene/propylene copolymer.
U.S. Pat. No. 4,025,560 discloses that instead of conventional inorganic inert supports, polytetrafluoroethylene, polyethylene, polystyrene and polypropylene are preferred as the inert support. The present invention relates to an improvement of the technique disclosed in this U.S. Patent.